Haven't been any 14" rumors that I have seen, but there is the 13" low-priced MacBook Air rumor.
The MacBook Air rumor is a little weird.
People think it is awkward for Apple to have so many product lines, especially when the MacBook and MacBook Air are fairly similar and the Air hasn't been properly updated for many years. The "official" rumor from an analyst or two says there will be a sub-$1000 13" MacBook Air coming out later this year.
Many assume the sub-$1000 MacBook Air will be rebranded as a MacBook and it will be $899.
Makes sense to me: ditch the ports and compress and compile and leave everything minimal and "yestertech" to achieve a $899 entry point for laptop Macs. Then offer modern MacBooks starting at $1099+ with DDR4 and larger SSDs, etc.
My big question: Will there be 13" MacBooks appearing this year, too?
Speculation believes there will be, and that the bezel will get the chop to allow the 13" on the current MacBook frame. The resolution of that Retina screen will be somewhere around the resolution of the old 30" ACD! Plenty of room for work.
Ultimately, I doubt the MacBook will go to 14" because it would require a bigger frame and a bigger price. MacBooks are meant to be mighty Mac netbooks that can do a lot more than mere netbooks. MacBooks are already very powerful for most all apps, but they lack the extra cores you get other Macs, so they are very limited when doing multi-core computing. Wait for Sept-Oct to see what rolls out; you might like it as much as a 14" dream.